PUNTA ESPINOZA - GREAT BLUE HERON, SEA TURTLE, FLIGHTLESS CORMORANT OH MY!!!
Fernandina Travel Blog› entry 15 of 22 › view all entries
(ANOTHER BEAUTIFUL DAY IN PARADISE, WHAT CAN I SAY?)
The Great Blue Heron , Ardea herodias, is a wading bird in the heron family Ardeidae, common over most of North and Central America as well as the West Indies and the Galápagos Islands, except for the far north and deserts and high mountains where there is no water for it to feed in. It is an extremely rare vagrant to Europe, with records from Spain, the Azores and England.
It is the largest North American heron, with a head-to-tail length of 91�"137 cm (36-54 in), a wingspan of 180 cm (71 in), and a weight of 2.
There are five subspecies:
* Ardea herodias herodias Linnaeus, 1758.
* Ardea herodias fannini Chapman, 1901. The Pacific Northwest from southern Alaska south to Washington; coastal.
* Ardea herodias wardi Ridgway, 1882. Kansas and Oklahoma to northern Florida.
* Ardea herodias occidentalis Audubon, 1835. Southern Florida, Caribbean islands.
* Ardea herodias cognata Bangs, 1903. Galápagos Islands.
The subspecies differ only slightly in size and plumage tone, with the exception of subspecies occidentalis, which as well as normal colored birds, also has a distinct a white morph, known as the Great White Heron.
The call is a harsh croak; they are most vocal during the breeding season, but will call occasionally at any time of the year in territorial disputes or if disturbed.
The Great Blue Heron is found throughout most of North America, including Alaska, British Columbia, Quebec, New Brunswick and Nova Scotia. The range extends south through Florida, Mexico and the Caribbean to South America.
The primary food for Great Blue Heron is small fish, though they are also known to eat shellfish, insects, rodents, amphibians, reptiles, and small birds. It is generally a solitary feeder. Individuals usually forage while standing in water, but will also forage in fields or drop from the air, or a perch, into water. As large wading birds, Great Blue Herons are able to feed in deeper waters, and thus are able to exploit a niche not open to most other heron species.
It feeds in shallow water or at the water's edge during both the night and the day, but especially around dawn and dusk. Herons locate their food by sight and generally swallow it whole. Herons have been known to choke on prey that is too large. It uses its long legs to wade through shallow water, and spears fish or frogs with its long, sharp bill.
This species usually breeds in monospecific colonies, in trees close to lakes or other wetlands; often with other species of herons.
These groups are called heronry (more accurately than "rookery").
Great Blue Herons build a bulky stick nest, and the female lays three to six pale blue eggs. One brood is raised each year. If the nest is abandoned or destroyed, the female may lay a replacement clutch. Reproduction is negatively affected by human disturbance, particularly during the beginning of nesting. Repeated human intrusion into nesting areas often results in nest failure, with abandonment of eggs or chicks.
Both parents feed the young at the nest by regurgitating food. Parent birds have been shown to consume up to four times as much food when they are feeding young chicks than when laying or incubating eggs.
Eggs are incubated for approximately 28 days and hatch asynchronously over a period of several days. The first chick to hatch usually becomes more experienced in food handling and aggressive interactions with siblings, and so often grows more quickly than the other chicks.
Birds east of the Rocky Mountains in the northern part of their range are migratory and winter in Central America or northern South America. From the southern United States southwards, and on the Pacific coast, they are year-round residents.However their hardiness is such that individuals often remain through cold northern winters, as well.
It has been recorded as a vagrant in Greenland, Hawaii, and the Azores.
The Great Blue Heron is replaced in the Old World by the very similar Grey Heron, which differs in being somewhat smaller (90�"98 cm), with a pale gray neck and legs, lacking the browner colors that Great Blue Heron has there. It forms a superspecies with this and also with the Cocoi Heron from South America, which differs in having more extensive black on the head, and a white breast and neck.
The "Great White Heron" could be confused with Great Egret but is larger, with yellow legs as opposed to the Great Egret's black legs. The Reddish Egret and Little Blue Heron could be mistaken for the Great Blue Heron, but are smaller, and lack white on the head and yellow in the bill.
Yes, the Great Blue Herons that you’ve seen back home in the USA and Canada are the same as the ones here in Galápagos. The Great Blue Heron (Ardea herodias) is a large, majestic bird that is relatively common in the United States and Canada, as well as Mexico and the West Indies. They can be found in South America as well. Great Blue Herons living in Canada and the northern United States migrate south to spend the winter, but they can be seen year-round in Galápagos. They are considered a non-endangered species.
The Great Blue Heron is a shore bird, and can often be seen wading in tidal pools looking for small fish. They have also been known to eat reptiles, turtles and even rodents. Great Blue Herons nest in colonies of several nests, occasionally with or near other heron species.
In Galapagos, Great Blue Herons can be found anywhere there are small fish in shallow water: look for them in tide pools, mangroves and sandy shores with some tree cover. The tidal pools near Cerro Brujo (San Cristobal) are a good place to look for them. In general, you won’t see any along exposed stretches of beach or inland. If you move slowly, you may be able to get rather close for a good photo.
The Galápagos Green Sea Turtle is a subspecies of the Green Turtle (Chelonia mydas).
The Galápagos Green Sea Turtle is a subpopulation of the Green Sea Turtle, Chelonia mydas. It is endemic to the tropical and subtropical waters of the Pacific Ocean (Koch, 2007). They are often categorized as one population of the east Pacific Green Turtle (Seminoff, 2002). This title is shared with the other Green Sea Turtle nesting populations inhabiting the Pacific Ocean. More specifically they are referred to as the Black Sea Turtle due to their unique dark pigmentation (Koch, 2007). The Galápagos Green Turtle is the only population of Green Sea Turtle to nest on the beaches of the Galápagos Islands and this fact is the derivative of their name (Green, 1984). There have been various debates over the binomial nomenclature of this population due to the distinct morphological characteristics that set them apart from other populations of Green Sea Turtle (Parham, 1996).
The mature adult Galápagos Green Turtle is much smaller than those of other Green Sea Turtle populations; this may be why they are more genetically isolated than other populations (Pritchard, 1999).
Galápagos Green Turtles get their name from their specific nesting habitat, the Galápagos Islands. They are the only subpopulation of sea turtle to nest in these islands (Green, 1993). The Galápagos straddle the equator off the coast of Ecuador and consist of 17 islands that are volcanic in origin (Green, 1984). This is not their only habitat as they are a highly migratory species and spend much of their time cruising the warm waters of the Pacific Ocean (Green, 1984). Colonies of Green Sea Turtles have been observed nesting in 80 countries around the globe and they forage along the coasts of ~140 countries (Seminoff, 2004).
Female Galápagos Green Turtles most often only lay eggs every 2-3 years and spend the time between resting and foraging (Chelonia).
Nesting most often occurs at night so there is protection from predators (Bowen, 1992). The prime season for nesting is from December to June (Koch, 2007), however peak months are January through March (Pritchard, 1971). Females are very uneasy when coming up to shore. If they feel threatened they will return to the water and wait until the shore is safer (Pritchard, 1971).
Green Sea Turtles have been recorded and observed in the Galápagos over many centuries as far back as the 1600’s by William Dampier (Green, 1984). There has not been much attention brought to them due to the overwhelming research done on the Galápagos Giant Tortoises (Pritchard, 1971). Only over the last 30 years have extensive studies been performed covering the behaviors of the Galápagos Green Turtles. Much of the debate that has surrounded them recently is over the binomial classification of the species (Parham, 1996).
Galápagos Green Turtles’ lifestyle is similar to other populations of Chelonians. The behavior of all Sea Turtles is difficult to track but many tagging experiments have been performed to assess migration patterns (Bowen, 1992) as well as feeding habits of Chelonians in the eastern Pacific (Seminoff, 2002). The results of this research indicates that the Green Sea Turtles of the eastern Pacific including the Galápagos Green Turtles are highly migratory and ingest many different variations of forage including some animal matter (Seminoff, 2002). The female Green Turtles are known to nest colonially and to return to the same nesting beach every time they reproduce (Bowen, 1992).
Behaviors of hatchlings differ form that of adults.
Economic Significance to Humans
Now that the Galápagos Green Turtle is an endangered species it has little positive economic significance for humans (Seminoff, 2004). They have in the past been harvested from egg to adult for various human uses (Seminoff, 2004). The eggs and meat from all life stages was utilized in many areas as a food source for humans and the meat is still considered a delicacy in some countries of South America (Koch, 2007). They were also harvested for their hides and for the oils of their fat deposits used in cooking, however the Galápagos Green Turtle has less body fat than other populations so not as much oil was yielded from their bodies (Pritchard, 1971). Now the Green Turtles have more of a negative impact on human economics due to their status as endangered (Seminoff, 2004). They are often involved as by catch in many ocean fisheries and are protected through many acts of legislation (Koch, 2007).
As previously noted the Galápagos Green Turtle, grouped with all populations of Chelonia mydas, is listed on the IUCN Red List of threatened species (Seminoff, 2004). They were placed on the list in the mid 1980’s and have remained under protection since (Seminoff, 2004). One of the major problems that have lead to their decline is the slow growth rate and long period from juvenile to sexual maturity (Seminoff, 2004). Chelonians average a period of 26-40 years to maturity; the Galápagos Green Turtle averages 33 years (Seminoff, 2004). The Green Sea Turtle has been shown to have the slowest growth rate of any species of Sea Turtle and is generally long-lived if left undisturbed (Seminoff, 2004). Over all populations of Chelonia mydas have seen a decrease of approximately 48-67% of nesting females, however the population that nests in the Galápagos has remained quite steady with little to no change (Seminoff, 2004). The population of nesting females recorded in the Galápagos from 1976-1982 was ~1400 individuals and after further evaluation in 1999-2001 they again found ~1400 nesting females (Seminoff, 2004).
Reductions in populations of Chelonia mydas are recorded in every ocean ecosystem that they inhabit and the contributing factors that have lead to their decline are all anthropogenic (Seminoff, 2004). The main threats are harvesting of eggs and individuals, by-catch in marine fisheries, and degradation of the marine and coastal habitats (Seminoff, 2004). The most common accidental threat is the entanglement in fishing equipment with the most harmful methods being drift netting, shrimp trawling, long-lining, and dynamite fishing (Seminoff, 2004). There are now many pieces of legislation that ban these practices in protected areas (Seminoff, 2004).
For Chelonians inhabiting the eastern Pacific, including the Galápagos Green Turtle, threats are the same. The main factor leading to decline in this area was the intense and unregulated fishing operations run off the coast of Mexico between 1950-1970 (Koch, 2007). In many countries in Central and South America the meat of Sea Turtles are considered a delicacy and they are to this day poached and hunted directly (Koch, 2007). The mortality of the Sea Turtles near their foraging area of the Baja California Peninsula is ~7800 deaths yearly and this has lead many organizations to rally for governmental protection of this area for the species (Koch, 2007). It was noted that approximately 9 out of 100 individuals will survive a year in the waters of the Baja California Peninsula and as previously stated this in an intense foraging ground for all population in the eastern Pacific (Koch, 2007). Even with the passing of new protective legislation and the many efforts of conservation organizations, populations are continuing to decline, and considering the long generation length of 42.8 years any hit on the population is difficult to recover from (Seminoff, 2004).
One of the many conservation efforts being implemented to increase populations at this time is the use of hatcheries for protected egg incubation (Pilcher, 2001). The goal of this type of project is to create a protected environment for the hatchlings where they can incubate and emerge from the sand without threat of predators and then be released out to sea safely (Pilcher, 2001). Unfortunately this is not the result that has been documented from the practice. Often when hatchlings emerge from the sand in the incubator they remain enclosed inside and expends much of their preserved energy trying to find a way out (Pilcher, 2001). They also lose the extremely important dark, night hours used to get far away from shore (Pilcher, 2001). When they are released out to sea it is often in the early morning hours of dusk when many predators are about and this limits their chance of survival (Pilcher, 2001). In addition to the threat of being released during dusk the hatchlings are also often too weak to gain a swift and long distance movement from shore due to the expended energy lost in the incubator after hatching (Pilcher, 2001). These results have lead many to believe that hatcheries are ineffective and should only be used as a last resort (Pilcher, 2001). There is no extensive research showing the survival rate of the hatchlings after they are released to sea but one study proclaimed a possible 50% loss after release (Pilcher, 2001)
The Flightless Cormorant (Phalacrocorax harrisi), also known as the Galapagos Cormorant, is a cormorant native to the Galapagos Islands, and an example of the highly unusual fauna there. It is unique in that it is the only cormorant that has lost the ability to fly. Once it was placed in its own genus, Nannopterum or Compsohalieus, although current taxonomy places it in the genus with most of the other cormorants, Phalacrocorax.
With only 1500 estimated individuals, it is one of the world's rarest birds and is the subject of an active conservation programme.
Like all cormorants, this bird has webbed feet and powerful legs that propel it though ocean waters as it seeks its prey of fish, eels, small octopuses, and other small creatures. They feed near the bottom and no more than 100 m offshore.
The Flightless Cormorant is the largest extant member of its family, 89�"100 cm (35-40 in) in length and weighing 2.5�"5.0 kg (5.5-11 lbs), and its wings are about one-third the size that would be required for a bird of its proportions to fly. The keel on the breastbone, where birds attach the large muscles needed for flight, is also greatly reduced.
The upperparts are blackish and the underparts are brown. The long beak is hooked at the tip and the eye is turquoise. Like all members of the cormorant family, all four toes are joined by webbed skin. Males and females are similar in appearance, although males tend to be larger. Juveniles are generally similar to adults but differ in that they are glossy black in colour with a dark eye. Adults produce low growling vocalisations.
Like other cormorants, this bird's feathers are not waterproof, and they spend time after each dive drying their small wings in the sunlight. Their flight and contour feathers are much like those of other cormorants, but their body feathers are much thicker, softer, denser, and more hair-like. They produce very little oil from their preen gland; it is the air trapped in their dense plumage that prevents them from becoming waterlogged.
Distribution and habitat
This unique cormorant is endemic to the Galapagos Islands, Ecuador, where it has a very restricted range. It is found on just two islands; Fernandina, where it is found mainly on the east coast, as well as on the northern and western coasts of Isabela. The population has undergone severe fluctuations; the 1983 El Niño event resulted in a 50% reduction of the population to just 400 individuals. The population recovered quickly, however, and was estimated to number 900 individuals in 1999.
This species inhabits the rocky shores of the volcanic islands on which it occurs. It forages in shallow coastal waters, including bays and straits and rarely ventures further than one kilometre from the breeding areas.
Nesting tends to take place during the coldest months (July�"October), when marine food is at its most abundant and the risk of heat stress to the chicks is decreased. At this time, breeding colonies consisting of around 12 pairs form. The courtship behaviour of this species begins in the sea; the male and female swim around each other with their necks bent into a snake-like position. They then move onto land. The bulky seaweed nest, located just above the high-tide mark, is augmented with "gifts" including pieces of flotsam such as rope and bottle caps, which are presented to the female by the male.
The female generally lays three whitish eggs per clutch, though usually only one chick survives. Both male and female share in incubation. Once the eggs have hatched, both parents continue to share responsibilities of feeding and brooding (protecting the chicks from exposure to heat and cold), but once the chicks are old enough to be independent, and if food supplies are plentiful, the female will leave the male to carry out further parenting, and she will leave to find a new mate. Females can breed three times in a single year. Thus, although their population size is small, Flightless Cormorants can recover fairly quickly from environmental disasters.
These cormorants evolved on an island habitat that was free of predators. Having no enemies, and taking its food primarily through diving along the food-rich shorelines, the bird eventually became flightless. However, since their discovery by man, the islands have not remained free of predators: cats, dogs, and pigs have been introduced to the islands over the years. In addition, these birds have no fear of man and can easily be approached and picked up.
In the past, introduced feral dogs were a great threat to the species on Isabela, but they have since been eradicated from the island. Future introduction of rats or cats to Fernandina is a huge potential threat to the species. Fishing with nets poses a current threat to the species; this not only reduces the availability of the cormorant's food, but also often results in birds becoming caught in the nets and killed.
The fact that this uniquely adapted bird is found in such a small range and in such small numbers greatly increases its vulnerability to chance events such as environmental disasters (especially oil pollution), extreme climatic events and the introduction of diseases or predators. Unfortunately, marine perturbations such as those caused by El Niño events are becoming increasingly extreme. Still, its ability to breed quickly can allow it to recover from disasters as long as the population remains above the critical level.
Because of these factors, the Flightless Cormorant is one of the world's rarest birds. A survey carried out by the Charles Darwin Research Station in 2004 indicated that the species has a population of about 1,500 individuals.
All populations of this species are found within the Galapagos National Park and Marine Reserve; furthermore, the archipelago was designated as a World Heritage Site in 1979. The Charles Darwin Research Station has monitored the species regularly to keep track of fluctuations in numbers over time. The species is considered vulnerable, and conservation proposals include the continuation of annual monitoring programmes, the reduction of disturbance by humans, and the prevention of fishing with nets in the bird's foraging range.
Isla Fernandina, Galapagos Islands, the third largest island in the Galapagos, Isla Fernandina is an interesting place to visit. With a total land area of 642 sq km, this island also known as Narborough and is the youngest of the five big Galapagos Islands. With a remarkable and striking volcanic landscape, the last time an eruption occurred here was in 1995 and according to experts, this island has the greatest likelihood of erupting again, making visiting here a must to see a chance eruption.
Make a dry landing at Punta Espinosa, which sits directly across Tagus Cove on Isla Isabela, to see the largest colony of marine iguanas in the Galapagos. Here, literally thousands of marine iguanas can be found along the rocky coast, either sitting on a rock or swimming in the water in search of food. Called an ugly creature when spotted by Darwin during his stay in the Galapagos, these marine iguanas are the only lizards that are known to swim in the world. Elegant and graceful swimmers, these algae eating iguanas are a sight to watch as the change color from a blackish green to amazing blues and reds during mating season. Some other island natives here include the Flightless Cormorant, sea lions and Galapagos penguins.
There are two walking trails on Isla Fernandina, one of which leads you to a lava field, where you can spot various plant species growing and thriving.